Synthesis of highly potent piperazine-linked benzothiazolyl-4-thiazolidinones via catalytic N-formylation: antibacterial drug design

A new series of piperazine-based benzothiazolyl-4-thiazolidinones has been yielded efficiently via highly accelerated N-formylation of 1-(4-methoxyphenyl) piperazine using sulfated tungstate, a mild heterogeneous catalyst. The formylated piperazine moiety was then condensed with substituted 2-aminobenzothiazoles to form corresponding Schiff base intermediates which were then treated with thioglycolic acid to equip a new class of 4-thiazolidinones. New products were examined for their antibacterial effects against two Gram-positive (S. aureus and B. subtilis) and two Gram-negative (E. coli and P. aeruginosa) strains and were highly potent with lowest MIC values 1–4 μg mL−1, more potent than control drugs ciprofloxacin (3.12–6.25 μg mL−1). The structural assignments of the new products were done on the basis of FT-IR, 1H NMR, 13C NMR spectroscopy, and elemental analysis.